1. Field of the Invention
The invention relates to the field of connectors, particularly connectors used for integrated circuit packages.
2. Prior Art
Recent advances in integrated circuit technology have made possible the extensive use of microcomputers. Most often these microcomputers include a microprocessor or central processing unit (CPU) which is coupled to other integrated circuits by printed circuits. For example, a CPU may be coupled to a clock generator, system controller, memories including PROMs, ROMs and RAMs, and peripheral units, such as a priority interrupt controller and bus driver. These microcomputers are often employed in specialized applications which require both unique hardware and software.
New test equipment and methods for microcomputers have been developed to permit "debugging" of both hardware and software. One such tool is the in-circuit emulator. These devices permit the simultaneous testing of both hardware and software. Most often the microprocessor or CPU is removed from its socket in the microcomputer. A connector then engages this socket and couples the microcomputer board to the emulator. A CPU or microprocessor identical to that used by the microcomputer is included within the emulator to permit emulation of microcomputer functions. Such emulators permit the interception of addresses, data, status information and other signals intended for the CPU or microprocessor, and the substitution or modification of these signals and the contents of memories and registers, in addition to other functions. These emulators often permit cycle-by-cycle operation of the microcomputer which greatly aids in isolating problems.
Emulators most often communicate with the microcomputer circuit board through a long umbilical cable which includes many leads (e.g. 40 leads). One such umbilical cable is shown schematically in Electronics, April 15, 1976 edition on page 117. In the centermost photograph on page 115 of this edition of Electronics, the cable and connector employed in one commercial emulator is shown. (This edition of Electronics describes numerous microcomputers and testing aids, including emulators.)
One problem with these emulators is that considerable time delay is introduced by the long umbilical cable. All the signals which flow between the CPU or microprocessor and the remainder of the microcomputer must pass through this cable. These time delays prevent real-time emulation, particularly for high performance microcomputers. In contrast, with the interconnector described in this application, the propagation delays associated with this emulator cable are substantially reduced. This enables better emulation and moreover, such emulation can be provided at a lower cost.